1. Field of the Invention
The present invention relates to a pixel structure of a transflective liquid crystal display (TR-LCD) panel and a method of making the same, and more particularly, to an amorphous silicon thin-film transistor (a-Si TFT), which has a pixel structure having a single cell gap, and a method of making the same.
2. Description of the Prior Art
The LCDs are mainly categorized into three types such as transmissive type LCDs, reflective type LCDs and transflective type LCDs due to their different types of illumination sources. The transmissive type LCD panel usually has a backlight source disposed therein so that the transmissive type LCD panel can be provided with illumination lights. The emitting lights coming from the backlight source can penetrate through the transmissive type LCD panel and therefore the viewers can see colorful display images created by the transmissive type LCD. The reflective type LCD panel has a reflection electrode disposed therein so that the ambient lights entering into the reflective type LCD panel from the display plane of the reflective type LCD panel can be reflected by the reflection electrode. Afterwards, the reflected lights will penetrate through the reflective type LCD panel again and therefore the viewers can see the display images created by the reflective type LCD. The transflective type LCD (TR-LCD) is a kind of LCD having both of the characteristics of the reflective type LCD and the transmissive type LCD. In other words, the TR-LCD can be operated either in reflective mode or operated in transmissive mode. In such a case, it is therefore that each pixel region of the TR-LCD panel includes a transmission region and a reflection region. The transmission region is illuminated by the backlight source, and the reflection region is illuminated by the ambient lights.
Conventional TR-LCD panels can be further classified into a single cell gap TR-LCD panel and a dual cell gap TR-LCD panel. The cell gap of the reflection region of the single cell gap TR-LCD panel is identical to that of the transmission region of the single cell gap TR-LCD panel. However, since the light path difference of the ambient light of the reflection region is not identical to that of the backlight source of the transmission region, the gamma curve of the reflection region is accordingly not identical to that of the transmission region. Consequently, an optimized optical efficiency operated either in reflective mode or operated in transmissive mode can not be looked after. The dual cell gap TR-LCD panel is different from the single cell gap TR-LCD panel. The cell gap of the reflection region of the dual cell gap TR-LCD panel is substantially about half of the cell gap of the transmission region of the dual cell gap TR-LCD panel so that the ambient lights of the reflection region and the backlight source of the transmission region substantially have the same light path difference. In such a case, the transmission region and reflection region have substantially consistent gamma curves. However, since the cell gap of the dual cell gap TR-LCD panel must be adjusted by virtue of arranging additional bumps in the reflection region, an additional manufacturing process should be performed for forming the bumps. As a consequence, the complexity of the manufacturing process and the production cost will increase.